Figure 1. A, Cumulative incidence of atrial fibrillation with respect to body mass index (BMI) group.

B, Association of BMI at conscription into military service with risk of early‐onset atrial fibrillation. The model was adjusted for age, conscription year as a spline with knots at 5%, 25%, 75%, and 95% (1972, 1979, 1994, and 2002), test center, systolic blood pressure, diastolic blood pressure, cardiorespiratory fitness, muscle strength, parental education, and baseline comorbidities (diabetes, hypertension, and adult congenital heart disease) (n=1 287 197). BMI of 15 to 50 kg/m² was modeled as a restricted cubic spline with knots at 5%, 25%, 75%, and 95% (18.1, 19.9, 23.2, and 27.2 kg/m²) with BMI of 20 kg/m² as reference.